The present invention relates to an evacuatable solar collector, comprising a collector tub, a radiotransparent pane sealingly covering the tub, an absorber arranged below the pane and support members passing through the absorber and having a limited cross-section whereby, during evacuation, said support members support the pane in punctiform manner from the inside in places distributed over the surface area thereof, against the action of the external atmospheric pressure.
DOS No. 27 28 019 discloses a solar collector, in which the rod-shaped or tubular support members rest directly on the collector bottom, which is typically formed by a metal sheet having a thickness of 1 mm to 2 mm. The resulting forces acting in almost punctiform manner on the collector bottom lead to the plastic deformation thereof at the points of the support members, so that, in time, the latter start to be marked towards the outside. This not only gives the appearance of gradual wear, to the solar collector, but also, in time, leads to changes in the static conditions with which the collector pane is supported. Thus, for example, on ventilating the collector, the cover pane comes away from the downwardly sagged support members, and conversely on evacuating the collector again, this must lead to the plate not being underpinned from the outset by the support members and is instead only drawn against them with an impact.